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Add --no-rs-codes flag to optionally disable reed-solomon codes in grub-install and grub-bios-setup for x86 BIOS targets.

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This commit is contained in:
Jon McCune 2013-12-09 16:52:12 -08:00
parent 7a148da6dd
commit dd73313cba
6 changed files with 81 additions and 23 deletions
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5
ChangeLog
View file

@ -1,3 +1,8 @@
2013-12-09 Jon McCune <jonmccune@google.com>
* Add --no-rs-codes flag to optionally disable reed-solomon codes
in grub-install and grub-bios-setup for x86 BIOS targets.
2013-12-09 Vladimir Serbinenko <phcoder@gmail.com>
Implement sparc64 trampolines (needed for sparc64-emu).

14
docs/grub.texi
View file

@ -5994,8 +5994,20 @@ mounted on
Recheck the device map, even if @file{/boot/grub/device.map} already
exists. You should use this option whenever you add/remove a disk
into/from your computer.
@end table
@item --no-rs-codes
By default on x86 BIOS systems, @command{grub-install} will use some
extra space in the bootloader embedding area for Reed-Solomon
error-correcting codes. This enables GRUB to still boot successfully
if some blocks are corrupted. The exact amount of protection offered
is dependent on available space in the embedding area. R sectors of
redundancy can tolerate up to R/2 corrupted sectors. This
redundancy may be cumbersome if attempting to cryptographically
validate the contents of the bootloader embedding area, or in more
modern systems with GPT-style partition tables (@pxref{BIOS
installation}) where GRUB does not reside in any unpartitioned space
outside of the MBR. Disable the Reed-Solomon codes with this option.
@end table
@node Invoking grub-mkconfig
@chapter Invoking grub-mkconfig

6
include/grub/util/install.h
View file

@ -183,12 +183,14 @@ void
grub_util_bios_setup (const char *dir,
const char *boot_file, const char *core_file,
const char *dest, int force,
int fs_probe, int allow_floppy);
int fs_probe, int allow_floppy,
int add_rs_codes);
void
grub_util_sparc_setup (const char *dir,
const char *boot_file, const char *core_file,
const char *dest, int force,
int fs_probe, int allow_floppy);
int fs_probe, int allow_floppy,
int add_rs_codes);
char *
grub_install_get_image_targets_string (void);

19
util/grub-install.c
View file

@ -68,6 +68,7 @@ static int have_load_cfg = 0;
static FILE * load_cfg_f = NULL;
static char *load_cfg;
static int install_bootsector = 1;
static int add_rs_codes = 1;
enum
{
@ -93,7 +94,8 @@ enum
OPTION_DEBUG_IMAGE,
OPTION_NO_FLOPPY,
OPTION_DISK_MODULE,
OPTION_NO_BOOTSECTOR
OPTION_NO_BOOTSECTOR,
OPTION_NO_RS_CODES,
};
static int fs_probe = 1;
@ -180,6 +182,10 @@ argp_parser (int key, char *arg, struct argp_state *state)
install_bootsector = 0;
return 0;
case OPTION_NO_RS_CODES:
add_rs_codes = 0;
return 0;
case OPTION_DEBUG:
verbosity++;
return 0;
@ -238,6 +244,9 @@ static struct argp_option options[] = {
N_("do not probe for filesystems in DEVICE"), 0},
{"no-bootsector", OPTION_NO_BOOTSECTOR, 0, 0,
N_("do not install bootsector"), 0},
{"no-rs-codes", OPTION_NO_RS_CODES, 0, 0,
N_("Do not apply any reed-solomon codes when embedding core.img. "
"This option is only available on x86 BIOS targets."), 0},
{"debug", OPTION_DEBUG, 0, OPTION_HIDDEN, 0, 2},
{"no-floppy", OPTION_NO_FLOPPY, 0, OPTION_HIDDEN, 0, 2},
@ -1435,12 +1444,13 @@ main (int argc, char *argv[])
"boot.img");
grub_install_copy_file (boot_img_src, boot_img, 1);
grub_util_info ("%sgrub-bios-setup %s %s %s %s --directory='%s' --device-map='%s' '%s'",
grub_util_info ("%sgrub-bios-setup %s %s %s %s %s --directory='%s' --device-map='%s' '%s'",
install_bootsector ? "" : "NOT RUNNING: ",
allow_floppy ? "--allow-floppy " : "",
verbosity ? "--verbose " : "",
force ? "--force " : "",
!fs_probe ? "--skip-fs-probe" : "",
!add_rs_codes ? "--no-rs-codes" : "",
platdir,
device_map,
install_device);
@ -1449,7 +1459,7 @@ main (int argc, char *argv[])
if (install_bootsector)
grub_util_bios_setup (platdir, "boot.img", "core.img",
install_drive, force,
fs_probe, allow_floppy);
fs_probe, allow_floppy, add_rs_codes);
break;
}
case GRUB_INSTALL_PLATFORM_SPARC64_IEEE1275:
@ -1475,7 +1485,8 @@ main (int argc, char *argv[])
if (install_bootsector)
grub_util_sparc_setup (platdir, "boot.img", "core.img",
install_device, force,
fs_probe, allow_floppy);
fs_probe, allow_floppy,
0 /* unused */ );
break;
}

19
util/grub-setup.c
View file

@ -64,6 +64,12 @@
#define DEFAULT_BOOT_FILE "boot.img"
#define DEFAULT_CORE_FILE "core.img"
/* Non-printable "keys" for arguments with no short form.
* See grub-core/gnulib/argp.h for details. */
enum {
NO_RS_CODES_KEY = 0x100,
};
static struct argp_option options[] = {
{"boot-image", 'b', N_("FILE"), 0,
N_("use FILE as the boot image [default=%s]"), 0},
@ -82,7 +88,9 @@ static struct argp_option options[] = {
/* TRANSLATORS: The potential breakage isn't limited to floppies but it's
likely to make the install unbootable from HDD. */
N_("make the drive also bootable as floppy (default for fdX devices). May break on some BIOSes."), 0},
{"no-rs-codes", NO_RS_CODES_KEY, 0, 0,
N_("Do not apply any reed-solomon codes when embedding core.img. "
"This option is only available on x86 BIOS targets."), 0},
{ 0, 0, 0, 0, 0, 0 }
};
@ -118,6 +126,7 @@ struct arguments
int fs_probe;
int allow_floppy;
char *device;
int add_rs_codes;
};
static error_t
@ -173,6 +182,10 @@ argp_parser (int key, char *arg, struct argp_state *state)
verbosity++;
break;
case NO_RS_CODES_KEY:
arguments->add_rs_codes = 0;
break;
case ARGP_KEY_ARG:
if (state->arg_num == 0)
arguments->device = xstrdup(arg);
@ -233,6 +246,7 @@ main (int argc, char *argv[])
/* Default option values. */
memset (&arguments, 0, sizeof (struct arguments));
arguments.fs_probe = 1;
arguments.add_rs_codes = 1;
/* Parse our arguments */
if (argp_parse (&argp, argc, argv, 0, 0, &arguments) != 0)
@ -292,7 +306,8 @@ main (int argc, char *argv[])
arguments.boot_file ? : DEFAULT_BOOT_FILE,
arguments.core_file ? : DEFAULT_CORE_FILE,
dest_dev, arguments.force,
arguments.fs_probe, arguments.allow_floppy);
arguments.fs_probe, arguments.allow_floppy,
arguments.add_rs_codes);
/* Free resources. */
grub_fini_all ();

23
util/setup.c
View file

@ -248,7 +248,8 @@ void
SETUP (const char *dir,
const char *boot_file, const char *core_file,
const char *dest, int force,
int fs_probe, int allow_floppy)
int fs_probe, int allow_floppy,
int add_rs_codes __attribute__ ((unused))) /* unused on sparc64 */
{
char *core_path;
char *boot_img, *core_img, *boot_path;
@ -486,7 +487,11 @@ SETUP (const char *dir,
nsec = core_sectors;
if (add_rs_codes)
maxsec = 2 * core_sectors;
else
maxsec = core_sectors;
if (maxsec > ((0x78000 - GRUB_KERNEL_I386_PC_LINK_ADDR)
>> GRUB_DISK_SECTOR_BITS))
maxsec = ((0x78000 - GRUB_KERNEL_I386_PC_LINK_ADDR)
@ -543,15 +548,16 @@ SETUP (const char *dir,
write_rootdev (root_dev, boot_img, bl.first_sector);
core_img = realloc (core_img, nsec * GRUB_DISK_SECTOR_SIZE);
/* Round up to the nearest sector boundary, and zero the extra memory */
core_img = xrealloc (core_img, nsec * GRUB_DISK_SECTOR_SIZE);
assert (core_img && (nsec * GRUB_DISK_SECTOR_SIZE >= core_size));
memset (core_img + core_size, 0, nsec * GRUB_DISK_SECTOR_SIZE - core_size);
bl.first_block = (struct grub_boot_blocklist *) (core_img
+ GRUB_DISK_SECTOR_SIZE
- sizeof (*bl.block));
grub_size_t no_rs_length;
grub_set_unaligned32 ((core_img + GRUB_DISK_SECTOR_SIZE
+ GRUB_KERNEL_I386_PC_REED_SOLOMON_REDUNDANCY),
grub_host_to_target32 (nsec * GRUB_DISK_SECTOR_SIZE - core_size));
no_rs_length = grub_target_to_host16
(grub_get_unaligned16 (core_img
+ GRUB_DISK_SECTOR_SIZE
@ -560,6 +566,12 @@ SETUP (const char *dir,
if (no_rs_length == 0xffff)
grub_util_error ("%s", _("core.img version mismatch"));
if (add_rs_codes)
{
grub_set_unaligned32 ((core_img + GRUB_DISK_SECTOR_SIZE
+ GRUB_KERNEL_I386_PC_REED_SOLOMON_REDUNDANCY),
grub_host_to_target32 (nsec * GRUB_DISK_SECTOR_SIZE - core_size));
void *tmp = xmalloc (core_size);
grub_memcpy (tmp, core_img, core_size);
grub_reed_solomon_add_redundancy (core_img + no_rs_length + GRUB_DISK_SECTOR_SIZE,
@ -568,6 +580,7 @@ SETUP (const char *dir,
- core_size);
assert (grub_memcmp (tmp, core_img, core_size) == 0);
free (tmp);
}
/* Write the core image onto the disk. */
for (i = 0; i < nsec; i++)